1. Field of the Invention
This invention relates, generally, to surgical tools and methods for their use. More particularly, it relates to a needle apparatus and a method for marking the location of a lesion or a tumor in a breast or soft tissue.
2. Description of the Prior Art
Mammography enables the detection of very small lesions or tumors in a breast, even if the individual is experiencing no symptoms. However, if the lesion or tumor is non-palpable, it can be difficult for the surgeon to locate it and remove it through surgery.
A lesion may be non-palpable because it is very small. It may even be relatively large, but still non-palpable because it resides in a large breast or in a smaller breast but deep within the tissue mass.
In one prior art procedure, developed by Kopans, a hypodermic needle is placed into the breast so that the tip of the needle is near the lesion.
After the needle tip is positioned near the lesion, a stainless steel wire having a thin hooked distal end is introduced into the proximal end of the hollow bore of the needle and pushed toward the lesion until the thin hooked distal end of the wire protrudes from the distal end of the needle. The wire is thickened near its distal end, purportedly to make the wire palpable. The hook engages the breast tissue in the vicinity of the lesion and holds the wire in place. Additional mammograms are then taken to verify the respective positions of the needle, the wire, and the hook. If the position of the apparatus is satisfactory, the needle is withdrawn from the breast, leaving the stainless steel wire unmoved because it is not connected to the needle. The surgeon then follows the wire to the lesion and removes the tissue in the vicinity of the hook.
The breast, however, must be compressed during the taking of a mammogram. The compression often causes the needle to migrate during mammagraphic filming; this causes uncertainty about the location of the hook.
Moreover, if the position of the hook is determined to be unsatisfactory, i.e., too far from the lesion, the hook cannot be extracted easily so that another attempt can be made to position it closer to the lesion. Forceful retraction of the hook can damage breast tissue. The hook might even break off and be lost in the tissue mass.
What is needed, then, is an improved method for marking the position of a breast lesion or tumor. The new method should facilitate additional attempts to better position the needle if the initial needle insertion proves to be unsatisfactory. There should be no tissue damage caused by withdrawing a wire hook and there should be no broken hooks left within a breast.
However, it was not obvious to those of ordinary skill in this art how the needed improvements could be provided, in view of the art considered as a whole at the time the present invention was made.